Succinic acid removal and recovery from aqueous solution using hydrotalcite granules: Experiments and modeling

Hydrotalcites (layered double hydroxides) are an alternative for anion removal due to their adsorption and ion exchange properties, e.g., in biotechnology. The applicability of powdered hydrotalcite in columns under dynamic conditions is impossible due to the small particle size and the low specific density. Therefore, the material was granulated for application as inorganic adsorbent in commercially available chromatographic columns. The calcination of a granulated hydrotalcite/betonite water mixture led to an open-porous material with a specific surface area of 153 m2/g. The average adsorption capacity of the hydrotalcite granules for succinic acid in column experiments was estimated at 0.4 mol/kg over 12 succeeding ad- and desorption cycles (pH 6.5). Up to 98% of the bound succinic acid could be recovered. The granules were characterized concerning their pore structure and adsorption equilibrium. The obtained results were included in a mathematical model simulating adequately the breakthrough behavior of the system.